Physcomitrium patens avodiiron proteins form heterotetrametric complexes
Pubblicato il: 02.10.2024 10:46
Photosynthesis is a fundamental process that sustains life on Earth by producing oxygen, regulating the levels of carbon dioxide (CO₂) in the atmosphere, providing food and energy as well as biomass for ecosystems. Ensuring an efficient photosynthetic process is fundamental for plant fitness. In fact, photons excite electrons in chlorophyll associated to photosystems, initiating an electron flow through the electron transport chain which are essential for converting carbon dioxide into glucose and finally for biomass production.
Plants are constantly exposed to varying light conditions, which can cause light stress and potentially damage their photosynthetic apparatus. Flavodiiron proteins (FLVs) play a crucial role in balancing electron flow within the photosynthetic machinery. These proteins act as safety valves, converting oxygen into water using electrons coming from photosystem I, thereby preventing its over-reduction and damage during dark-to-light transitions.
In the study titled “Physcomitrium patens flavodiiron proteins form heterotetrameric complexes” the authors focus on two specific FLV isoforms, FLVA and FLVB, from the moss Physcomitrium patens. By expressing and purifying these proteins in Escherichia coli, they discovered that both FLVA and FLVB bind iron and flavin cofactors and exhibit key enzymatic activities, including NAD(P)H oxidase and oxygen reductase capacities. Most notably, when co-expressed, these proteins form a FLVA/B heterotetrameric complex, stabilized by inter-subunit disulfide bonds, which is stable and catalytically active.
These findings provide valuable insights into the structural and functional properties of FLVs, enhancing our understanding of how photosynthetic organisms manage light stress and maintain the integrity of their photosynthetic systems, and paving the way for a deeper comprehension of photosynthesis.
Claudia Beraldo, Eleonora Traverso, Marco Boschin, Laura Cendron, Tomas Morosinotto, Alessandro Alboresi. Physcomitrium patens flavodiiron proteins form heterotetrametric complexes. Journal of Biological Chemistry, 2024,107643, ISSN 0021-9258, doi.org/10.1016/j.jbc.2024.107643.
